Process of manufacturing dies



F. HONIG Pz'wcsss OF muumcwuame DIES Filed June 9. 1921 I G H INVEN TOR.

Him/K Ho/v/a 3% J l A TTORNEYS Patented July 26, 1927.

mam: HONIG, 01 OAK PARK, ILLINQIS, ASS IGNOB CHICAGO, ILLINOIS, A CORPORATION T CYCLO coaroaa'nou, or or rumors.

PROCESS OF. MANUFACTURING IlDIES.

Application filed June 9,

This invention relates particularly 'to dies for wire-drawing purposes and to a method of manufacturing the same. The invention is applicable, however, to dies for various I purposes. 7

The primary object is to provide a die havin greatly improved wear-reslsting qualities. A further object is to provlde an improved method of manufacturing dies, en-

1O abling a die of long life to be manufactured quite cheaply. 4

In accordance with this invention, a composite die is formed which possessesa body of great strength, preferably steel, and wh ch possesses a wear-resisting operat ve portion of great hardness, the W88.IIS1tl11g portion being preferably tungsten containing a small ercenta e of carbon the operative portion ing subjected to special treatment in the U process of manufacture.

The method of practicing the invention is illustrated in the accompanying drawlng, in which Fig. 1 represents a bar or rodof tungsten;

ll Fig. 2, a sectional view of the steel body portion of the die; Fi 3, a similar section showing the tungsten bar entered in the recess with which the body-portion is provided;

Fig. 4, a broken view of a water-cooled tool for forming the tungsten after it has been reduced to a molten condition; Fig. 5, a

sectional view of the die previous to the drilling operation; and Fig. 6, a sectional view of the finished die, the View showing brokenly a piece of rod which is being drawn into wire.

As shown in Fig. 6, the die comprises a steel body portion A containing an insert of tungsten A. g

In the preferred method of manufacture, the body A is first formed in the shape shown in Fig. 2, being in approximately cylindrical form and provided with a bore or recess 1 which has a tapered or flaring end portion 1 at one end of the block. At the other end of the bore 1, the block has an end wall 2.

A bar of tungsten 3 is introduced into the bore 1; the body A of the die is introduced into a water-cooled cup-shaped terminal or electrode B; another electrode C is applied to the upper end of the piece of tungsten; and, by means of electric current, the tu sten bar is melted, so as to fill or partia y 1921. Serial No. 478,115.

fill the lower portion of the cup-shaped body A. After the tungsten has been melted, the water-cooled pointed tool 0 is introduced and employed to cool and mold the tungsten body. During the period of solidification of the tungsten, it is subjected to ressure which is increased as the solidification progrosses. If desired, either'the pointed tool C or the body of the die may be subjected to comparatively slow rotation during the period of compression. 'The action of coolmg and compressing the tungsten has the result of preventing the formation of the ordinary characteristic crystalline agglomeration of the particles or molecules of the tungsten, and the working of the tool (involving compression with or without rotationhtends to improve the structure of the tlngsten for the desired purpose. The effect 0 t 1e ditions is to render the tungsten more dense and hard at the inclined or conical surface 4; which is formed by the pointed tool, this being the portion ofthe metal which is operative in effecting the reduction of the wire as it is drawn. It may, perhaps, be more accurately said that the tungsten, containing a percentage of carbon, is melted or rendered sufficiently fluid to fill or conform to the matrix in the steel block and that by the use of the water-cooled pointed tool, applied with suitable and preferably continued pressure, the surface is chilled while the pressure is applied. Since tungsten melts at an extremely high temperature (about 3400" C., see Smithsonian Physical Tables, 1921) and carbon sublimes at about 3500 C. (idem), it is altogether probable'that tungsten carbides, or carbide, are formed and that the chilling fixes these carbides at and near the chilled surface. In any event the metal at the surface is extremely hard (scratching anything except diamond), and the hardness decreases from the surface inwardly. It may be added that a small percentage of carbon; say from 1% to 3%,will suffice to give to the tungsten the desired characteristics. While it is believed that the carbon is fixed in acombined state, or as a carbide, at and near the chilled surface and is perhaps deposited and held more and more in solid SOllltlOIlfiS the depth from the surface increases, it is unnecessary to commit oneself definitely to any theory of explanapressure and working under these contion of the improved result. In any event the carbon serves as a hardening a nt, an this is particularly true at or near t e chilled surface of the tungsten body.

It will be understood by those skilled 1n the metallur cal art that the melting of the tungsten an the operation thereon should be effected in a non-oxidizing atmosphere, as, for example, a hydrogen atmosphere. An suitable provision may be employed to one le this to be accomplished, no special provision bein here shown. The bar of tun ten may obtained by any suitable metlihd of manufacture for example, tungsten trioxide ma be re need in a current of hydro n and t e tungsten powder may be melte and cast in a mold. Or, if desired, t powder may be mixed with some bin material and assed thru a steel die to produce the rod. n whatever manner the tungsten may be repared initially, it should be provided, he ore being used in the manufacture of dies, with a sultable carbon constituent. -It is preferred to have the tun ten practically are, but with a small carl idn content, whic should not exceed a few per cent.

It may be said that in the manufacture of the die, the heat of the electric current and also the heat of the molten tungsten serves to melt or soften a portion of the steel suporting body of the die; and the tungsten comes thoroughly welded to the steel. At the junction between the tungsltien and the steel, an alloy is formed. e tungsten penetrates the steel to a certain extent, and,

conversely, the steel enetrates the tungsten to a certain extent; e working surface of the tungsten practically is however, pure tunfiten, containing a sma percentage of car n.

After the tan n insert or core has been introduced in t e manner described, a perforation 4 is drilled through the center of the block, the u per end' of this perforation merging with e conical surface 4 formed by the pointed tool. After the drilling operation, which cannot be erformed by ordlna'riy drilling methods, at must be accomp ished by the method used in drilling diamond dies, the surface of the bore is lapped, ground or made smooth in any desired manner. The inner surface ofthe die is subjected to a charging operation, in which operation graphite, or other solid lubricating material, such as limestone or soapstone is caused to fill the pores or openings in the metal at the operative surface of the die. This is effected by introduci graphite and grinding it into the' pores t)? the surface by means of a tool hardened and ound to fit the form of the interior surface of the die. This is effected under heavy ressure, the pressure being preferably higher than the diewould be exposed to when wire is drawn therethru. The high pressure'serves to charge the minute openmgs of the tungsten or steel, as the case may be, with the solid lubricant, thus insurin an exceedingly smooth wearing surface, an

an unbroken film of lubricatin material at such surface. In the use of th e die, additional lubricant is introduced, of course, as v the wire-drawing operation proceeds. It may be added that tungsten has a great affinity for carbon, and where graphite or carbon is used as a solid lubricantduring a wire-drawing operation, the die tends to keep its surface charged with a sufiicient carbon content to maintain the best wearing surface.

It may be stated that if the tungsten body has been melted, and worked into virtually integral formation with the steel cup by of 500,000 pounds per square inch. Accordingllyl', the life of the ordinary steel die, or the lghest grade steel alloy dies is comparativel short. The improved die possesses the requisite strength, increased hardness and su erior wear-resistin properties.

hile it is preferre to make the working surface of the die of tungsten, it may be stated that steel, or suitable steel alloy, may itself be subjected to the improved process with highly beneficial results. For example, the die may be composed wholly of tungsten and steel, which may be reduced to a molten condition while confined in a suitable mold, and then subjected to a chilling, pressing and mechanical working operat1on, as by means of a. ointed tool, in much the manner describe This will result in increasing the density, hardening to a certain extent, and generally improving the wear-resisting qualities of the die.

Moreover, the ,method of charging the wear-surface of the die with solid lubricant, such as gra hite, which has been described, may be app 'ed to ordinary dies with benefi'cial results. For exam le, steeldies may be subjected to an operation of chargin the ores of their wear surfaces with a' soli lu-' ricant b pressing the lubricant into the pores un er intense pressure, at the same time turning or operating the tool so as to, m effect, grlnd the lubricant into the pores and to some extent harden the wear surface of the die. In this manner, dies may be produced which w1ll permit a wire-drawing its as a solid lubricant ground into the pores at the wear-surface of the die, it being noted that graphite gives a markedly better result for this pulpose than could beobtained from any other cm of solid lubricant, such as soapstone. When the method first described herein is followed in the manufacture of the i die, the efiiciency of the .die over the bestknown dies may be even greater.

The improved process enables dies of superior qualit to be produced at moderate expense; an the improved dies enable w re-drawing machines to be operated at eatly increased speeds, thereby greatly reucing the cost of roduction of wire. Moreover, the increased life of the die itself is an important factor in the economy of manufacture of wire.

While the invention possesses great value in connection with dies for wire-drawing purposes, it isevident that the invention may be applied to dies for other purposes. For example, a steel supporting body havin a shell or wear surface of tungsten applied thereto may be produced substantially 1n the manner described. For some purpose, it may be desirable 'to produce dies for punching operations in this manner. Thus, the female die may be lined with a tungsten body and the male die may be encased in a tungsten shell, so that the operative surfaces are of tungsten while the bodies of the dies are steel, giving the necessary strength and also desirable cheapness. Any suitable metal or alloy of sufiicient strength may be used as an equivalent of the steel in the supporting block.

The foregoing detailed description has been given for clearness of understanding only, and no unnecessary limitations should be understood therefrom, but the appended claims should be construed as broadly as permissible in view of the prior art.

What I regard as new, and desire to secure by Letters Patent, is-

. 1. The process of making a die which comprises bringing a molten body compr sing tungsten and a hardening agent into contact with a supporting body of steel and welding the two together and subjecting the tungsten body to pressure during the period of solidification.

2. The process of makmg a. d1e which comprises providing a steel block with a recess, forming a molten body of tungsten the improved wearand a'hardening agent in said recess, and sub ecting the tun sten to pressure during the period of solidification.

a die which he process of makin comprises providing a steeF block with a recess, forming a molten bodyoftungst'en and a hardening agent in said recesspand S'UbJBCtlIlg the tungsten to shaping pressure and surface chilling during the period of solidification.

4. The presure of making a die whichcomprises forming a cup-shaped steel block, introducing therein a bar comprisin tungstemand a hardening agent. meltmg'the bar in the bore of the cup, and subjecting the tungsten body to pressure by means of a pointed tool during the period of solidification.

5 The method of manufacturing a die which comprises forming a steel supporting body, melting a body comprising tungsten and a hardening agent in contact with said supporting body to provide a working portion, and subjecting the tungsten body to pressure and surface chilling during the period of solidification of said body and a substantial portion of the period of cooling thereof. a

6. The method of forming a die which comprises introducing a body comprising tungsten and carbon into a on body, introducing the steel ody into an artificially cooled electrode, appl ing. an electrode to the tungsten body, me ting the tungsten bodp:l by'means of an electric current passed t rough the electrodes and the -shaped steel intervening tungsten body. and subjecting ing a steel block with a bore having a ta pered orifice'at one end of the block. the other end of the-block presenting a closed wall. introducing a. bar comprising tungsten and a hardening agent into said bore, melting the tungsten body in situ, subjecting the tungsten body to the consolidating action of a. pointed tool during the period of solidification, and then boring a hole through the tungsten body and the bottom of the steel block.

8. The method of making a die for wire drawing pur oses which comprises providing a steel block with a bore having a tapered orifice at one end of the block, the other end of the block presenting a closed wall, introducing a tungsten bar into said bore, melting'the tungsten bar in situ, subjecting the tungsten to pressure by a. pointed tool during the period of solidification, thus producing a conical recess in the tungsten and condensing and hardening the tungsten. then boring a hole. through the tungsten and the bottom of the steel cup. and then chargpressure during the ing the working surface of the tungsten with a solid lubricant.

9. The process of making a die which comprises melting a body of tungsten containing a small percentage by weight of carbon in contact with a steel body, and consolidating the tungsten body and the steel body under pressure accompanied by a surface chilling of the tungsten body.

10. The process of making a the which comprises providing a steel block with a recess, reducing to molten condition in said recess tungsten containing a small percentage by weight of carbon, and sub ectmg the tungsten body to pressure and cooling wh le consolidating the tungsten and steel bodies into integral formation.

11. The process of making a die which comprises welding and press-forming a molten body comprising tungsten and a hardening agent onto a steel support-ing base and subJecting the tungsten body to a working operation during the coohng period.

12. The process of making a the which comprises welding and press-forming a molten tungsten body containing a small percentage by weight of carbon onto a steel body, consolidating said bodiesamder pressure accompanied by surface chilling of the tungsten body, an working the tungsten body before it hascompletely solidified.

13. In the manufacture of an apertured die, the method which comprises subjecting tungsten and carbon to a temperature near the subliming temperature of carbon, until the tungsten is substantially molten, pressforming the body so as to provide a converging cavity ada ted to afford a wear-surface, and then drilling a hole at the central portion of said cavity while substantially preserving the surrounding pressed surface as a wear-surface.

14. In the manufacture of an apertured die, the method which comprises subjecting tungsten and carbon to a temperature near the subliming temperature of carbon until' the tungsten is substantially molten, pressforming the body so as to provide a converging cavity adapted to afford a wear-surface and simultaneously chilling said surface, and then drilling a hole at the central portion of said cavity while substantially preserving the surrounding pressed surface as a wear-surface.

15. In the manufacture of an ap'ertured die, the process which comprises introducing into a supporting metal body provided with a bore and a bottom wall a body comprising tungsten and a small percentage by weight of carbon, subjecting the introduced body to a temperature near the subliming temperature of carbon until the tungsten is substantially molten, press-forming the tungsten body so as to provide a converging cavity solidlubricant is caused to c ada ted to aiford a wear-surface, and then dril ing a hole at the central portion of said cavity while substantially preserving the surrounding pressed surface as a wear-surface.

16. In the manufacture of an apertured die, the steps which comprise introducing into a cup-shaped metal-supporting member a body comprising tungsten and a small per-- f-cen'tage by weight of carbon, melting the tungsten in situ, and subjecting the introduced body to shaping and working accompanied by surface chilling before complete solidification has occurred.

18. In the manufacture of an a ertured die, the steps which comprise sub ecting a molten body of tungsten containin a small percentage by weight of carbon to t 1e working] and cooling action of a cooled pointed too 19. In the manufacture of a die, the method which comprises reducing to substan' tially molten condition within a confining wall a tungsten body containing a hardenin agent, and forming and simultaneously coo ing the surface of said body during the period of solidification.

20. In the manufacture of a die, the method which comprises reducing to substantially molten condition a tungsten body containing a hardeningagent and forming said body under pressure accompanied by working and simultaneously chilling the surface of the body.

21. In the manufacture of a die, the method which comprises reducing to substantially molten condition, a tungsten body associated with ahardening agent, forming said body and simultaneously chillin a surface thereof, and subsequently grin ing carbonaceous material into the pores of the wear-surface of the'die'.

22. The process of producing a die which comprises subjecting the wear-surface of the die to pressure and mechanical working, with a solid lubricant interposed between the wear-surface and the working tool, whereby arge the pores of the wear-surface of the die.

23. The process of producing a die which comprises grinding into the wear-surface of the die a solid lubricant by introducing such lubricant between said wear-surface and tool and causing a relative rotation of said partswhile the parts are maintained under heavy pressure,

FRANK HONIG. 

